The present invention relates to a unit for overwrapping packets.
The invention finds application to advantage in the manufacture of tobacco products, relating as it does to the operation of overwrapping packets that contain such products, and in particular packets of cigarettes, to which reference is made explicitly throughout the following specification albeit with no limitation in general scope implied.
More particularly, the present invention relates to a unit for overwrapping packets substantially of rectangular prismatic geometry, delimited axially by two opposite end faces, and delimited laterally by two larger side faces and by two smaller side faces extending parallel to a longitudinal axis of the rectangular prism. The packets are overwrapped as they advance in a predetermined direction along a predetermined wrapping path.
Such units generally include feed devices serving to advance leaves of overwrapping material obtained by cutting a continuous strip of the material as it decoils from a relative roll.
Modern packaging machines are capable of notably high operating speeds, especially continuous motion cigarette packers of which the overwrapping units in question form a part. To ensure that products will emerge faultlessly overwrapped, therefore, it becomes more and more important that the leaves of overwrapping material remain under continuous and complete control as they are advanced by the feed devices, in order to avoid any kind of problem that could derive from incorrect positioning and loss of timing, causing the leaf to be applied defectively to the packet and producing an overwrap spoiled by unsightly creases or similar flaws.
The object of the present invention is to provide a unit for overwrapping packets such as will be able to fulfil the requirements mentioned above when operating at the high production tempo typical of a modern packaging machine.